A population expert who advises Chinese politicians has warned that China faces a serious threat from the gender imbalance caused by the widespread preference for sons over daughters.
Abortion or even infanticide of girl babies means that in some areas there are now as many as 130 men for every 100 women - so that many young men have no-one to marry, and there are growing problems with prostitution and abduction of women.
Louisa Lim reports on the causes and social consequences of the Chinese bias against girls.
And Elisabeth Croll, Professor of Chinese Anthropology at the School of African and Oriental Studies and journalist, Zhang Lijia joins Martha to talk about the issues.
